What is sub query in SQL?

Question

Can anyone explain the sub query in SQL?

Answer 1

The subquery is the inner query of the nested query. The outer query in the nested query uses the output from the subquery. We can use a subquery in where clause of select, insert, update, and delete statements.

Here is a syntax to write subquery in SQL:

SELECT ColumnName

FROM TableName

WHERE ColumnName operator

                (Select ColumnName from TableName where condition);

You can check out this SQL tutorial blog by Intellipaat to learn writing complex subqueries in SQL.